Phascolarctos cinereus (Goldfuss, 1817)

Russell A. Mittermeier & Don E. Wilson, 2015, Phascolarctida, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 400-417 : 416-417

Koala

Phascolarctos cinereus

French: Koala / German: Koala / Spanish: Koala

Other common names: Koala Bear, Monkey Bear, Native Bear

Taxonomy. Lipurus cinereus Goldfuss, 1817 , New South Wales, Australia.

This species has historically included three subspecies: adustus from Queensland, nominate cinereus from New South Wales, and victor from Victoria and South Australia. An assessment of the mtDNA variation confirmed that geographically distinct populations represented a single evolutionary significant unit and that morphological differences may be better interpreted as clinal variation and not subspecific. Monotypic.

Distribution. E & SE Australia, widespread but somewhat patchy distribution from near Cairns in N Queensland down E Australia through New South Wales, Victoria, and across to SE South Australia. Introduced in various Is of Queensland and Victoria, and in several localities of South Australia.

Descriptive notes. Head-body 67-82 cm (males) and 65-73 cm (females); weight 4-2— 14-9 kg (males) and 4.1-11 kg (females). Koalas are large and arboreal, with vestigial tails and woolly fur. They show strong sexual dimorphism in body size and weight, and significant differences in size and weight occurs between smaller Queensland Koalas and the larger Victorian and South Australian Koalas. They have white ventral fur throughout their distribution. Individuals to the north have relatively shorter pale gray fur on their backs; those to the south have longer, gray-brown fur.

Habitat. Wet and dry sclerophyll forests in eastern Australia. Throughout this distribution, Koalas occur in forests and woodlands dominated by different species of eucalypt trees.

Food and Feeding. Koalas are arboreal folivores and highly selective browsers that consume almost exclusively leaves oftrees ofthe genus Eucalyptus (Myrtaceae) , primarily upon species of the subgenus genus Symphyomyrtus, with c.400 species. Of the 600 or more species in the genus Fucalyptus ( Myrtaceae ) in Australia, the Koala has been observed feeding on orsitting in only 120 species of trees. About 20 of these can be considered primary food sources. Koalas have also been observed in or feeding on fewer than 30 non-eucalypt species, including Acacia (Fabaceae) , Allocasuarina (Casuarinaceae) , Banksia (Proteaceae) , Callitris (Cupressaceae) , Hakea (Proteaceae) , Leptospermum , and Melaleuca (both Myrtaceae ). The typical foliage consumed by Koalas consists of 55% water, 15% fiber, 13% tannins and fiber, 7% starch, 6% lipids, and 4% protein. High fiber content of eucalypt foliage fills the stomach quickly and reduces the amount of food that can be consumed, and it has little nutritional value.

Breeding. Koalas have a distinct breeding season in September-May, with a peak of births in November—March. Females generally become sexually mature at c.24 months of age. Male Koalas are sexually mature at c.18 months of age but are typically prevented from gaining access to females by older, larger males until they reach their peak weight at c.4 years of age. Mating induces ovulation in female Koalas. The female gives birth to a single offspring (rarely twins) after a gestation of 34-36 days. If the female loses her single pouch young, she apparently cannot mate again and produce another young in the same breeding season. Young first emerge from the pouch at c¢.6 months of age, at which time the transition from the mother’s milk to eucalypt leaves begins.

Activity patterns. Koalas are typically inactive 18-20 hours/day and are largely nocturnal. In warm weather, Koalas can often be found reclining against a branch or lying on their stomach or even sometimes their back, with their arms extended on either side of the branch to increase heat loss. In the height of summer, Koalas will come down to the ground to seek shade.

Movements, Home range and Social organization. Koalas are largely solitary, spending c.86% oftheir time alone during the breeding season and up to 93% of the non-breeding season alone, although females may have a single offspring with them. The home ranges of males and females are similar but typically vary greatly between localities. They can range in size from less than c.1 ha to more than 300 ha but are most often 1-10 ha.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The conservation status of the Koala is listed as Least Concern because ofits wide distribution and presumably large overall population and because it is thought not to be declining at the rate required to qualify for listing in a threatened category. Historically, Koalas had a largely continuous distribution; however,as a result of habitat loss, drought, hunting, and disease, Koala populations rapidly declined and by the 1930s, they were present in less than 50% of their previous distribution. They have since returned to some parts of their former distribution through natural recovery in Queensland and active reintroduction programs from island populations in Victoria and South Australia. Their recovery has not been complete, however, because their geographical distribution has contracted significantly since European settlement. For example, in Queensland, the extent of Koala occurrence and area of occupancy is estimated to have contracted by c.30%, and much of New South Walesstill has only sparse populations. In New South Wales, Koalas are uncommon in most locations but are relatively common in the Pilliga region in the north of the State. In Victoria, they are common throughout most of the State, which has resulted in their being overly abundant in many locations. The Koala became extinct in South Australia by 1920, but it was subsequently reintroduced there. As part of the recovery process, the Koala has been introduced into areas where it was not recorded historically. Koalas were introduced on Kangaroo Island in 1923-1925 when 18 individuals were transferred from French Island, Victoria. They have also been introduced in Adelaide and Mount Lofty ranges, Eyre Peninsula, and the Riverland in South Australia. Although these re-established populations in Victoria and South Australia may be considered a success, there have been problems, including over browsing and a loss of genetic diversity that has resulted in inbreeding depression. Koalas have also been introduced, or in several cases have naturally migrated, to various islands off the coast of eastern and southern Australia. Adjacent to the state of Queensland, they have occurred on Magnetic, Newry, Rabbit, Brampton, Saint Bees, Quion, Fraser, Bribie, North Stradbroke, and Coochiemudlo islands. Of these, they are no longer thought to occur on Quion, Fraser, and Bribie islands. Hallstrom Island off the coast of New South Wales had introduced Koalas, but they no longer occur there. Three Hummock Island off the northern coast of Tasmania also had an unsuccessful introduction of Koalas. They have been introduced to variousislands off the coast of Victoria, including French, Phillip, Churchill, Quail, Chinaman, Snake, Saint Margaret, Raymond, and Rotamah. Of these islands, they no longer occur on Quail and Chinaman.

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Figures

Distribution. E & SE Australia, widespread but somewhat patchy distribution from near Cairns in N Queensland down E Australia through New South Wales, Victoria, and across to SE South Australia. Introduced in various Is of Queensland and Victoria, and in several localities of South Australia.